An RS-25 engine is expected to throttle up to 113 percent of rated power for the first time in a milestone test-firing on Wednesday. Development Engine 0528 (E0528) will be hot fired for about four minutes in the A-1 test stand at the Stennis Space Center in Mississippi to give NASA and prime contractor Aerojet Rocketdyne a first look at how the engine operates at this higher power setting.

The last hot-fire test in a long test series with E0528 is focused on development objectives for hardware that is being delivered from new manufacturing processes as a part of the RS-25 Production Restart Program. Newly built engines will support future Space Launch System (SLS) launches.In an email, Philip Benefield, Systems and Requirements Team Lead for the SLS Liquid Engines Office, told NASASpaceflight.com that the two primary objectives for this test center around running the engine at the new throttle setting.“[There are] Two primary objectives: demonstrate engine performance at 113% RPL (Rated Power Level) [and] demonstrate SLM POGO stability and performance at 113% RPL,” he said. “This will be the first test an RS-25 (or SSME) has ever operated at 113% RPL.”The pogo accumulator assembly is the first ...